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DOI	10.1130/B30154.1
	Metamorphic rocks in central Tibet: Lateral variations and implications for crustal structure
	Pullen, Alex; Kapp, Paul; Gehrels, George E.; Ding, Lin; Zhang, Qinghai
通讯作者	Pullen, A (通讯作者)
发表日期	2011
ISSN	0016-7606
EISSN	1943-2674
起始页码	585
结束页码	600
卷号	123 期号:3-4
英文摘要	Insights about lateral variations in the age, composition, and structure of the central Tibetan crust are provided by geologic investigations of metamorphic rocks in the Qiangtang terrane. Previous studies have shown that a tectonic melange of Triassic age with blueschist- and eclogite-bearing blocks within a greenschist-facies matrix is exposed over an E-W distance of similar to 600 km in the central Qiangtang terrane. New mapping shows that the melange extends over a N-S distance of similar to 150 km, nearly to the trace of the early Mesozoic Jinsha suture in the north. The melange, exposed structurally beneath Upper Paleozoic to Mesozoic strata in the footwalls of early Mesozoic normal faults, is composed mostly of Paleozoic metasedimentary and crystalline rocks. These findings support the hypothesis that a large part of the central and northern Qiangtang terrane crust is composed of supracrustal rocks. The Duguer Range, <25 km south of the southernmost melange, exposes high-temperature, low-pressure metasedimentary rocks and orthogneisses with 476-471 Ma U-Pb crystallization ages that represent continental basement of the Qiangtang terrane. The boundary at the surface between melange and Gondwanan basement corresponds closely with abrupt changes in crustal geophysical properties, and allows us to extrapolate this relationship to depth. The resultant crustal structure can be explained by development of major Mesozoic structures documented in surface geology. Antiformal geophysical features imaged in the midcrust are likely inherited from Mesozoic tectonics, suggesting that the crust may not have been as mobile as that required by models invoking large-scale lower-crustal flow beneath the central Tibet Plateau during the Cenozoic India-Asian collision.
关键词	TECTONIC EVOLUTION CONTINENTAL-CRUST KARAKORAM FAULT SEDIMENTS BENEATH QIANGTANG TERRANE SIERRA-NEVADA HIGH-PRESSURE ZIRCON AGES LHASA SUBDUCTION
语种	英语
WOS研究方向	Geology
WOS类目	Geosciences, Multidisciplinary
WOS记录号	WOS:000286665300011
来源期刊	GEOLOGICAL SOCIETY OF AMERICA BULLETIN
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/257878
推荐引用方式 GB/T 7714	Pullen, Alex,Kapp, Paul,Gehrels, George E.,et al. Metamorphic rocks in central Tibet: Lateral variations and implications for crustal structure[J]. 中国科学院青藏高原研究所,2011,123(3-4).
APA	Pullen, Alex,Kapp, Paul,Gehrels, George E.,Ding, Lin,&Zhang, Qinghai.(2011).Metamorphic rocks in central Tibet: Lateral variations and implications for crustal structure.GEOLOGICAL SOCIETY OF AMERICA BULLETIN,123(3-4).
MLA	Pullen, Alex,et al."Metamorphic rocks in central Tibet: Lateral variations and implications for crustal structure".GEOLOGICAL SOCIETY OF AMERICA BULLETIN 123.3-4(2011).